It's probably a function of going to a brand name school + killing the Google style interviews. If you do that and have multiple offers you probably get the average up. SV in general is nuts wrt to housing and rent so that's going to steadily push things up as well. Then certain markets are winner take all so it makes some sense to "over" pay for talent. This would create a bimodal distribution as well. If you work as a software eng in a biotech your pay will probably be less than at Google on average b/c the biotech has less need for a highly qualified say distributed systems engineer. So they will accept a different candidate out of the talent pool. Also the talent may want to work at the biotech for reasons other intangible reasons. H1B is just a guarantee for some employees over some term. So H1B sets the bottom of the market really. There is no reason to work a job or somewhere that pays less than an H1B level wage unless you've got some crazy stock options or something.